I gave a reading at an inn in Oxford County last August. It was a lovely old summer place by a lake, and afterwards a woman came up to me to introduce herself, and I noticed her necklace. A jeweler had made a caste of a seaweed blade, long and delicate, with air bladders and side branching. The necklace was a gleaming silver.

Ascophyllum! I said. She laughed and said, yes - yes it is.

I thought, well, things are changing. And they are. Seaweed is not only around our necks but also on our minds these days for making new things, some of them as lovely as jewelry to others such as growing seaweeds for biofuels.

When I give talks I remind my audience that marine conservation biologists work hard and long at their chosen fields. Their cautionary concerns, their alarms and fears, need to be listened to. I get testy when I read about establishing human colonies on the moon or on Mars because I think we should be getting things in order here first. It is past time to focus more attention on our oceans, to take a long look beneath the surface of the water to begin to understand the essentials of biological diversity in these places we do not easily or often see, to protect habitats and species we have damaged and overexploited, and to try to identify those that were, in some cases, destroyed entirely. Without an international effort, the ongoing harm we do will become, surely, more heartbreaking and catastrophic.

My interest these days is with seaweeds, the habitats they create, the myriad of species that live among them, and how some beneficial effects from these inshore coves and bays can spread into the deeper and wider places in the oceans.

I have been reading about new ideas for how humans might expand their use of seaweeds. One of them is to incorporate a portion of processed seaweed meal into cattle feed to reduce the methane gas the animals emit. Methane, a greenhouse gas, contributes to the planet’s warming. In this country, approximately 25% of our methane emissions come from cattle, but seaweed, included in their diet, diminishes the bacterial process in a cow’s gut that creates it. Ongoing experiments adding various amounts and species of seaweed meal to cattle feed confirm that it does so consistently.

But there is a concern. Seaweeds, while contributing nutrients, may not deliver adequate protein to promote cattle health. More tests need to be done on the animals that are fed this new diet, and on their meat and milk.

However, a few red flags already pop up. One is that a company testing seaweeds for cattle feed has developed a seed bank for a particular Pacific species, hoping to export their aquaculture techniques to various places around the world. The species they are using has a wide range in tropical to temperate waters. But if they plan to introduce it to new sites, invasive species of seaweeds can alter marine environments. Cleaning up invasives of any kind is expensive, sometimes impossible, and they can easily disrupt and overpower native habitats and native species. As a caution, international laws need to be in place so that taking seaweed species from one region and seeding aquaculture projects with them in another region where they are not endemic is prohibited, and that protection of native species of all kinds is a priority.

But the most basic red flag is this: there are too many domestic cattle on the planet. As I write this, Brazil is considering cutting more Amazon forests for more cattle ranches. There are already over 1,002 billion head of cattle in the world. The amount of pasture, feed, and water they need to supply us with the milk and meat we in developed nations have come to expect is vast.

In January of this year a study was published in the Lancet on how we can help protect the planet by making changes to the ways we eat. The first recommendation is to reduce our intake of red meat, to cut down on milk and cheese, and to convert some, but certainly not all, of our pastures and hay fields to grow crops such as nuts, legumes, whole grains, fruits and vegetables which can feed many more people well. Since there will be many more people to feed in the future, reducing our dependence on red meat would accomplish two things. One is it would free up land to grow healthy food that could nourish people in poorer countries. The other is that a diet of mostly, but not exclusively, plant-based foods is a healthier diet for richer countries that have come to depend on high red meat and milk consumption.

If we reduce the worldwide number of cattle we raise, methane in the atmosphere will go down. And this new food study in the Lancet, if engaged, would promote the health of all people, and of the land, both farmed and wild. If we were willing to shift our diets somewhat, reduce the number of cattle, and grow native seaweeds in small, independently owned aquaculture sites to augment cattle feed, rather than in large industrial sites, we’d all be better off. There are a lot of “ifs” in this paragraph, but this is not something that we can’t do. We just have to want to do it. It’s a part of getting things in order here on Earth.

Seaweed Chronicles came out on August 7. Since then, I have been giving radio interviews and speaking and reading at a number of events. It is a big change from the concentrated silence of putting a book together, but what encourages me is the public’s interest in the inshore habitat, its seaweeds and wildlife, and its health.

We are moving into a time of increasing climate shifts. One way to meet them is to make sure that our wild systems are not fractured or polluted or overharvested, that they are as healthy as we can make them. How else can we prepare them for the assault of temperature and rising water?

I have been asked for a list of businesses that sell species of wild-cut and aquaculture-harvested seaweeds as sea vegetables. You can easily find a complete list on the Internet of all seaweed enterprises on both the East and West Coasts.

Here are the businesses of the harvesters who are featured in my book and who spent so much time – with such patience – to teach me what I needed to know:

A preview of the Seaweed Chronicles cover. Over four years ago, I began research for a book about seaweeds. I knew about them only because I live by the shore, and they are a part of the daily landscape - high tide and low.

These past years of learning and writing have given me a sense of the complicated depth of wild systems and the immense value of preserving them, as well as the need for coastal people to make a living.

Seaweed has figured in coastal cultures for hundreds of years, and its uses are growing. My book is about seaweed species, the wild lives they feed and shelter, the harvesters who cut seaweeds, and the aquaculturists who grow them. It explores the work of scientists who protect habitats that are essential to the wellbeing of the oceans, and those who struggle to provide jobs for coastal people.

The book, Seaweed Chronicles: A World at the Water's Edge, will be in bookstores mid-August.